The Surprisingly Humanlike Ways Animals Feel Pain

A hurt rabbit pins back its ears and narrows its eyes—part of a "grimace scale" that tells us how animals feel discomfort.

Don't tell someone who just stapled a string of Christmas lights to their hand, but pain can be a good thing.

Pain is a messenger: It tells us that there's a problem and that we need to take care of it.

People can express discomfort, but animals sometimes have a tougher time. This led Weird Animal Question of the Week to wonder: "Do animals feel pain the same way we do, and how can we tell?" (Related: "Yes, Animals Think And Feel. Here’s How We Know.")

Show Us Where It Hurts

Mammals share the same nervous system, neurochemicals, perceptions, and emotions, all of which are integrated into the experience of pain, says Marc Bekoff, evolutionary biologist and author.

There are some clues as to how animals—especially pets—communicate physical suffering.

For instance, Dorothy Brown’s dog Foster has phantom limb pain in a leg that was amputated after being hit by a car.

“He will be fast asleep and jump up and cry and look at where his leg used to be,” says Brown, who teaches surgery at the University of Pennsylvania’s Veterinary Hospital, where Foster was brought in for treatment. Human amputees also experience this phenomenon.

Veterinarians also rely on observant owners to report behavioral changes that may indicate painful conditions, such as no longer jumping up on the couch or a loss of appetite, Brown adds. (See "Four Weird Ways Animals Sense the World.")

So there's some science behind owners' and vets' assertion that "I can see it in their eyes and I can see it in their face,” Brown says.

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Giant tortoises mate at Charles Darwin Station.

Photograph by Inga Spence, Alamy

I Feel Ya

Interpreting pain gets more challenging with non-mammals such as reptiles, which "can't make facial expressions like mammals—many don't even have eyelids,” Bree Putman, postdoctoral fellow at the Natural History Museum of Los Angeles, says via email.

But that doesn’t mean they don’t hurt: "Reptiles, amphibians, and fish have the neuroanatomy necessary to perceive pain," according to the book Pain Management in Veterinary Practice.